Structure of thin current sheets in the magnetotail

Thin current sheets with a thickness of less than a few ion gyro radii are known to play an important role in the energy conversion process in the magnetotail. During summer 2003, when the tetrahedron scale of Cluster was about 250 km, fine structures of thin current sheets were resolved using multipoint measurements. We examined the detailed structures of thin current sheets and their evolution during two substorm intervals with quite different characteristics: one event with clear signatures of reconnection and one without signatures of reconnection but clear oscillation of the thin current sheet.